The invention relates to a mixing and dispensing apparatus and method, particularly for preparing a hydro-seeding mixture or slurry for dispensing to a helicopter-carried slurry dispersal apparatus.
Hydro-seeding refers to a process wherein a settable slurry containing seeds is dispersed on selected sites that would otherwise be subject to erosion, e.g. steep loose slopes, so that when the slurry is set, heavy precipitation is unlikely to remove the slurry, enabling the seeds to take root in the steep slopes. It is well known that steep slopes are subject to erosion from precipitation such as rain and snow, specially when such slopes have been clear--cut of trees, or have roads traversing them, particularly in rugged unstable mountainous terrain. It is known to spray hydro-seeding material onto such areas, but usually the material is sprayed from dispersal apparatus carried on a truck which gains access to the site usually by road. In areas where the roads have been washed out, or the area is otherwise impassable to trucks, it is known to prepare the slurry at a truck base closest to the selected site, and to dispense the slurry to dispersal apparatus carried by a helicopter, which then transports the material to the site, sprays the site from the air, and then returns to the truck base for a further load of hydro-seeding slurry. Helicopters are very costly to operate, and if the helicopter has to travel a long way from the truck base to the site to be treated with hydro-seeding, or the helicopter must wait excessively for the mixture to be prepared and/or dispensed, operating costs become prohibitive.
Hydro-seeding slurry is usually prepared from ingredients closely adjacent the site where it is to be sprayed so as to reduce transportation of water, which is usually the heaviest ingredient of the mixture. Water is normally obtained from a convenient nearby source, such as a creek or lake, and the hydro-seeding slurry is prepared on site in a mixing apparatus prior to dispensing the mixture to a dispersal container carried by the helicopter. The dispersal container is fitted with a dispersal apparatus, usually a rotary slinger which rotates about a generally vertical axis and slings the hydro-seeding slurry onto the site to be treated. The hydro-seeding slurry has four main constituents, namely water, fertilizer, a gum or bonding agent such as guam gum, and seeds which are usually mixed with a fibrous material such as chopped wood waste, peat moss etc. The seeds and fibrous material are usually packaged in compressed bales to facilitate storage and transportation, but because the bales are relatively tightly compressed they do not readily mix with water unless they are first broken into smaller pieces, for example by shredding. While shredding can be performed manually, it is a slow process and can delay preparation of the final mixture, which can result in wasted time for the helicopter. It is important that the persons shredding the bale can break up the bale sufficiently quickly to enable batches of mixture of consistent quality to be produced on an essentially continuous basis, so as to essentially eliminate waiting time for helicopters.